1. Field of the Invention
The present invention relates generally to a supply system for providing breathing gases to a recipient and, more particularly, to a lightweight, easily maintainable passenger oxygen mask for providing oxygen to an aircraft passenger or crew member.
2. Discussion of the Prior Art
At altitudes over 12,000 feet there is insufficient oxygen in the air for a person to remain alert and responsive, and because the level of oxygen in the air decreases further at higher altitudes, a person's health may be endangered by the lack of oxygen if ambient air is not supplemented.
It is known to provide oxygen supply equipment for supplying oxygen to an aircraft passenger when the normal supply of oxygen within the cabin of an aircraft is interrupted at altitudes over 12,000 feet.
Typically, the known type of system includes a face mask adapted to fit over the mouth and nose of the passenger and a reservoir bag in communication with the face mask for supplying a predetermined volume of oxygen to the mask. The bag is also connected to a hose which delivers oxygen to the bag from an oxygen supply. A flow indicator is typically provided on the hose, and a pull cord is affixed to the hose and to a valve in the supply system for initiating oxygen flow when the hose and cord are pulled from a storage location.
Although various constructions of the known type of system are employed in the art, each such construction secures the face mask, bag and hose together by a piece of string or the like within the bag which is attached at one end to the face mask and at the opposite end to the hose. The string prevents the face mask from being pulled from the bag and hose, adding strength to the assembly.
In order to maintain the reliability of aircraft passenger oxygen supply systems, the systems are inspected after every 5,000 hours of flight time of the aircraft, and the reservoir bag of each oxygen mask is replaced with a new bag. Unfortunately, because conventional masks use a string between the face mask and the supply tube, it is necessary to cut this string in order to remove the bag, and a new string must be tied between the mask and hose when a new bag is installed.
It would be desirable to provide a construction possessing the familiarity of known systems, while simplifying the construction and maintenance of the oxygen mask. Further, it would be beneficial to eliminate the need for a string in the device in order to simplify replacement of the reservoir bag.